Pin tumbler lock structure



June 5, 1951 R. cIcERF, JR

Pin TUMBLER LOCK STRUCTURE Original Filed Nov. 18, 1947 5 Flea;

FIG.4

105 INVENTOR 04A Hafiz-n7- C. CERF-Iv. 95A

97A P99 5 Q ATTORNEY Patented June 5, 1951 PIN TUMBLER LOCK STRUCTURE Robert C. Cerf, J-r., Los Angeles, Calif., assignor to Hollymade Hardware Manufacturing Company, Los Angeles, Calif., a corporation of Cali fornia Original application November 18, 1947, Serial No. 786,727. Divided and this application September 11, 1948, Serial No. 48,825

This invention relates to improvements in pin tumbler cylinder locks.

This application is a division of my co-pending patent application Serial No. 286,727, filed November 18, 1 947.

One object of my invention is to provide an improved pin tumbler type cylinder look. A further object is to provide a pin tumbler cylinder lock in which the pull out position of the key may be readily detected by the fingers holding the key or by sound.

These and other objects are attained by my invention which will be understood from the following description and the accompanying drawings in which:

Figure l is a side elevational view of a pin tumbler key plug with protruding pins and inserted key, before grinding and fitting;

Figure 2 is a top plan view of an assembled cylinder lock of the removable type;

Figure 3 is a side elevational view partly in section of the assembled lock shown in Figure 2;

Figure 4 is a typical cross-sectional view showing a key plug, an inserted key, and a rounded'end tumbler pin, of the usual form made by hand filing;

Figure 5 is a cross-sectional view showing a key plug with an inserted key, a hole for a tumbler pin, a land around said hole, and a fiat end tumbler pin finished to a level with the land, of my improved form made by grinding;

Figure 6 is an enlarged cross-sectional view taken on the line l2l2 of Figure 3; and

Figure 7 is an enlarged fragmentary cross-sectional view showing the cylinder, driving pins, key, key plug, and a hand-filed rounded outer end tumbler pin.

It has been the usual practice, in finishing the transverse sliding tumbler pins of a cylinder lock having a key plug to insert the selected notched key (which is to be used for turning the key plug and operating the lock mechanism) into the key slot, put over-length tumbler pins in the holes in the plug, and then by hand filing to finish the pins so that the outer end point is in the plane of the cylindrical outer surface of the plug. During hand filing, the pins are turned axially so that when finished, the plug may be turned by the key no matter in what radial position the pins may be disposed in the holes. This results in a generally rounded end IMA as shown particularly in Figures 4 and '7, with the rounded outermost point lying in the outer cylindrical surface of the plug, and with the margin generally below the plugs cylindrical surface. Heretofore,

3 Claims. (01. 70-364) no machine has been available to perform the filing of the tumbler pins to the proper end shape and length to be operated by a selected key. I have found that if a small level land is formed on the plug adjacent and surrounding the outer ends of the transverse holes for the tumbler then the outer ends of the tumbler pins may be plane surfaces perpendicular to the axis of each hole and level with said land. When the plug is thus modified, the tumbler pins may be fitted by grinding the ends fiat and perpendicular to the land. This may readily be accomplished, and with precision by grinding off the over-length tumbler pins simultaneously with the formation of the land around the holes for said pins, while keeping the notched key in place in the key slot of the plug. This may be rapidly andeconomically carried out by well lniown grinder machine operations.

Referring to the drawings, an improved transverse sliding pin tumbler cylinder lock of the removable type is shown in Figures 2, 3, and 6, the cylinder body 96 being provided with a key plug 97 having transverse holes in which are fitted the tumbler pins 95 having flat upper end surfaces its level with the adjacent land 98 on the plug @i, said plug being adapted to be turned in the cylindrical opening in the body by the notched key I80 positioned in the key slot 99,

only when the tumbler pins 95 are suitably positioned from their inner ends by the notches in! in the key Hi0, this turning of the plug 9'1 actuating the latching means through the spindle I02. The tumbler pins 95 are pressed against the key notches Hill by the corresponding driver pins 93, which slide in holes in the driver pin boss 9 I, being held under the compression springs 94 which abut the slide cover Hi3 closing the outer end of the boss 9|. When the plug 91 is turned to approach the position at which the key 1% may be withdrawn from the key slot 99, the driver pins 93 (whose contacting ends I05 are smoothly rounded) press at their tips upon the land 93 to give a slight clicking sound and a distinct feel to the fingers of the person who is turning the key. The key pull-out position is thus clearly and definitely indicated. With the conventional hand filed pins 95A in a plug 91A having no land (as shown for comparison in Figures 4 and 7) no click or feel is evidenced when the driver pin 93 and the tumbler pins 95A are in alignment, i. e. when the key I may be withdrawn, because the outer end IMA of the tumbler pins A, being filed to the radius of the outer surface of the plug, ride smoothly nder the substantially spherical ends I05 of the driver pins 93. The provision of the land on the key plug, and the forming of flat outer ends on the tumbler pins not only solves the problem in operating the lock of positioning the plug for withdrawal of the key, but also permits the machine finishing of the plug and tumbler pins, and avoids the slow,

tedious, and expensive old operation of hand filing the pins.

The typical pin tumbler plug 91 with protruding pins 95 and an inserted key I90, which constitutes the assembly on which grinding is performed, is shown particularly in Figure l. The tumbler pins 95 are arranged in five holes at right angles to the plug axis so that the ends of the pins drop into notches llll in the key in accordance with any desired combination of notches. The overlength pins are then ground off so that the outer ends are level with an adjacent land 99 on the cylindrical plug 9?. It will be clear that it is essential to have the key fully inserted in the key slot 99 of the plug 9'5 in order that the pins 95 may be levelled ofi to the surface of the land 98 and of proper length to allow rotation of the plug 91 by the key I09 in the cylindrical hole in the lock body 99.

The advantages of my invention will be apparent. By simultaneously forming the land on the plug, and grinding the ends of the pins to that level, the finishing and key fitting operation may be performed on a semi-automatic grinding machine and laborious hand filing of the pins is avoided. The tumbler pin and plug assembly, with fiat pins and the land, provides a pin tumbler cylinder lock of improved performance, and at lowered costs.

I claim:

1. In a transverse sliding pin tumbler cylinder lock, a key plug adapted for turning in the cylindrical bore of said lock, said plug being provided with a key slot, with radial tumbler pin holes aligned parallel to said key slot, and with a plane land on the plug adjacent said pin holes, said plane land intersecting the cylinder surface at the level of the outer ends of said tumbler pin holes, and being perpendicular to the axes of said pin holes.

2. In a transverse sliding pin tumbler cylinder look, a key plug adapted for turning in the cylindrical bore of said lock, said plug being provided with a key slot, with radial tumbler pin holes aligned parallel to said key slot, and with a plane land on the plug disposed adjacent said pin holes; and tumbler pins in said pin holes, the outer ends of said pins being plane surfaces arranged parallel to said land, and level with said land when a matching key is inserted in the key slot.

3. A pin tumbler cylinder lock comprising a body having a cylindrical bore extending from the front face of said body and having a driven pin boss extending radially and parallel to said cylindrical bore, said boss having driver pin holes therein extending to said bore; a key plug in said cylindrical bore, said plug being provided with a key slot and with tumbler pin holes aligned with said driver in holes insaid body, and said plug also having a flat land adjacent said tumbler pin holes and perpendicular to the axes of said holes; spring-pressed driver pins in said driver pin holes, said driver pins having smooth rounded inner ends in sliding contact with the outer surface of said plug; and tumbler pins in said tumbler pin holes, said tumbler pins having fiat outer ends, said fiat ends being level with said land on said plug when a matching key is inserted in said key slot.

ROBERT C. CERF, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 446,192 Sargent et a1. Feb. 10, 1891 2,179,947 Miller Nov. 14, 1939 2,202,329 Braune May 28, 1940 2,276,655 Jacobi Mar. 1'7, 1942 FOREIGN PATENTS Number Country Date 690,883 Germany May 9, 1940 

